DE4031732A1 - RADIATION-RESISTABLE, AQUEOUS BINDER DISPERSIONS - Google Patents

Description

The invention relates to radiation-curable, aqueous binders dispersions containing

• A) 5 to 95% by weight, based on the total amount of components (A), (B) and (C) a water-dispersed polyurethane which has a K value greater than 40 (measured in dimethylformamide) or in dimethyl formamide is not soluble and contains polymerizable ethylenically unsaturated groups of a maximum of 0.2 mol per 100 g Has polyurethane, and
• B) 5 to 95% by weight, based on the total amount of components (A), (B) and (C) a water-dispersed prepolymer or prepolymer mixture containing 0.1 to 1.0 mol of polymerizable ethylenically unsaturated groups per 100 g of prepolymer or Prepolymer mixture and a molecular weight of 300 to 10,000, where the K value (measured in dimethylformamide) is less than 40, and
• C) 0 to 30% by weight, based on the total amount of components (A), (B) and (C), a protective colloid.

Radiation-curable, aqueous binder dispersions of polyurethanes, Polyesters, polyethers and other prepolymers are e.g. B. from the DE-A-28 53 921, known. DE-A-34 37 918 contains aqueous polyurethane Described acrylate dispersions in which the polyurethane acrylates Double bond number from 2.5 to 15 g bromine per 100 g polyurethane acrylate ( 0.016 to 0.09 mol of bromine or mol of double bonds per 100 g of poly have urethane acrylate). The Be produced with these dispersions Layers are characterized by good elastic properties. On due to the small number of double bonds and the associated However, the hardness of these coatings is low crosslinking density insufficient.

The object of the present invention was therefore aqueous, radiation-curable Binder dispersions, the coatings with very good elasticity and result in great hardness. At the same time, the coatings should be on substrate Adhere well to surfaces and are good solvent and chemical resistant show speed.  

Accordingly, the aqueous, radiation-curable binder dispersions found according to claim 1.

The other statements concern the individual components of the bandage medium dispersions and their use for coating surfaces.

Suitable polyurethanes (A) are obtained by reacting Polyiso cyanates with polyamines or polyols as chain extenders, given if given with monofunctional alcohol or amine compounds and if with compounds with at least one ethylenically unsaturated Group and at least one hydroxyl or isocyanate reactive Amino group.

In particular, in the manufacture of the polyurethane, based on

• a) 1 gram equivalent of NCO of a polyisocyanate following gram equivalent sets of compounds with one or more groups reactive towards isocyanate:
• b) 0.1-0.8 gram equivalents of OH of a polyol with a molecular weight between 400 and 6000 g / mol
• c) 0-0.8 gram equivalents of OH of a polyol with a molecular weight between 62 and 399 g / mol
• d) 0-0.4 gram equivalents of NH of a polyamine with at least two amino groups reactive towards isocyanate
• e) 0-0.4 gram equivalents of OH of an amino alcohol with one opposite Isocyanate reactive amino group
• f) 0-0.5 preferably 0.05-0.5 gram equivalents of OH or NH of a ver bond with ionic groups or convertible into ion groups Groups with at least one isocyanate-reactive Hydroxyl or amino group,
• g) 0-0.2 gram equivalents of OH or NH of monofunctional amine or Hydroxyl compounds and if necessary  
• h) as many grams equivalents OH of a compound with at least one ethylenically unsaturated group that in the polyurethane a maximum of 0.2 mol polymerizable ethylenically unsaturated groups (C = C groups) are present per 100 g of the polyurethane,

where the sum of the gram equivalents of the isocyanate reactive Amino and hydroxyl groups in general 0.9 to 1.1, in particular 0.95 is up to 1.05.

The content of polymerizable ethylenically is preferably saturated groups in the polyurethane 0.01 to 0.2, particularly preferably 0.02 to 0.08 mol per 100 g of the polyurethane.

The polyurethane has a K value (according to Fikentscher, Cellulose-Chemie 13, 58 (1932)) measured in dimethylformamide at 25 ° C of more than 40 or at 25 ° C in dimethylformamide, e.g. B. due to its particularly high Molecular weight or because it is a cross-linked polyurethane, insoluble, so that a K value can no longer be determined.

The following should be noted regarding the structural components of the ethylenically unsaturated polyurethane:
Suitable polyisocyanates a) are organic compounds which have at least two free isocyanate groups. Diisocyanates X (NCO) ₂ are preferably used, where X is an aliphatic hydrocarbon radical with 4 to 12 carbon atoms, a cycloaliphatic hydrocarbon radical with 6 to 15 hydrocarbon atoms, an aromatic hydrocarbon radical with 6 to 15 hydrocarbon atoms or an araliphatic hydrocarbon radical with 7 to 15 carbon atoms. Examples of such diisocyanates are tetramethylene diisocyanate, hexamethylene diiso cyanate, dodecamethylene diisocyanate, 1,4-diisocyanato-cyclohexane, 1-iso cyanato-3,5,5-trimethyl-5-isocyanatomethylcyclohexane, 4,4'-diisocyanato dicyclohexylmethane, 4,4 ′ -Diisocyanato-dicyclohexylpropane- (2,2), 1,4-di isocyanatobenzene, 2,4-diisocyanato-toluene, 2,6-diisocyanatotoluene, 4,4'-diisocyanato-diphenylmethane, p-xylylene diisocyanate, and those consisting of these compounds Mixtures, in particular mixtures of aliphatic or cycloaliphatic and aromatic diisocyanates in a molar ratio of 1: 4 to 5: 1. It is also possible to use the higher-functionality polyisocyanates known per se in polyurethane chemistry or else modified ones known per se, for example carbodiimide groups, allophanate groups, iso cyanurate groups, urethane groups and / or biuret groups containing poly isocyanates.

For the polyols b) of the molecular weight range between 400 and 6000 g / mol, preferably 800 to 4000 g / mol, particularly preferably 1400 to 3000 g / mol, it is polyester polyols or polyether polyols.

The polyester polyols are in particular those per se known reaction products of polyvalent, preferably divalent and optionally additionally trihydric alcohols with polyhydric, preferably dibasic carboxylic acids. Instead of the free polycarbonate Acids can also be the corresponding polycarboxylic anhydrides or ent speaking polycarboxylic acid esters of lower alcohols or mixtures thereof be used to prepare the polyester polyols. The polycarbonate Acids can be aliphatic, cycloaliphatic, aromatic or hetero be cyclic and optionally, e.g. B. substituted by halogen atoms and / or be unsaturated. Examples include: Succinic acid, adipic acid, suberic acid, azelaic acid, sebacic acid, Phthalic acid, isophthalic acid, trimellitic acid, phthalic anhydride, Tetrahydrophthalic anhydride, hexahydrophthalic anhydride, tetrachlor phthalic anhydride, endomethylene tetrahydrophthalic anhydride, glutar acid anhydride, maleic acid, maleic anhydride, fumaric acid, dimers Fatty acids. As polyhydric alcohols such. B. ethylene glycol, propylene glycol- (1,2) and - (1,3), butanediol- (1,4), - (1,3) and - (2,3), butene diol- (1,4), butynediol- (1,4), pentanediol- (1,5), hexanediol- (1,6), octane diol- (1.8), neopentyl glycol, cyclohexanedimethanol (1,4-bis-hydroxymethyl cyclohexane), 2-methyl-1,3-propanediol, pentanediol- (1,5), glycerol, Trimethylolpropane, hexanetriol- (1,2,6), butanetriol- (1,2,4), trimethylol ethane, also diethylene glycol, triethylene glycol, tetraethylene glycol, Polyethylene glycol, dipropylene glycol, polypropylene glycol, dibutylene glycol and polybutylene glycols in question.

Lactone-based polyester polyols are also suitable, these being Homopolymers or copolymers of lactones, preferably difunctional, addition products of lactones with terminal hydroxyl groups or lactone mixtures, such as. B. ε-caprolactone, β-propiolactone, ν-butyrene acton and / or methyl-ε-caprolactone to suitable difunctional starters molecules, e.g. B. the above as a structural component for the polyester poly ole low molecular weight, dihydric alcohols. The ent Talking polymers of ε-caprolactone are particularly preferred. Also lower polyester diols or polyether diols can be used as starters position of the lactone polymers used. Instead of the polymer Sates of lactones can also have the corresponding, chemically equivalent Polycondensates of the hydroxycarboxylic acids corresponding to the lactones be set.  

The - optionally mixed with polyester polyols - usable poly ether polyols, in particular diols, are in particular by polymerization of ethylene oxide, propylene oxide, butylene oxide, tetrahydrofuran, styrene oxide or epichlorohydrin with themselves, for. B. in the presence of BF ₃ or by the addition of these compounds, optionally in a mixture or one after the other, to starting components with reactive hydrogen atoms, such as alcohols or amines, for. B. water, ethylene glycol, propylene glycol (1,3) or - (1,2), 4,4'-dihydroxy-diphenylpropane, aniline available.

As polyols c) with a molecular weight between 62 and 399 g / mol, are z. B. the corresponding listed under b) for the production the polyester polyols suitable diols and triols, and higher than trifunk tional alcohols such as pentaerythritol or sorbitol.

The components d) which may be used are at least difunctional amine chain extenders or crosslinkers of the mol weight range from 32 to 500 g / mol, preferably from 60 to 300 g / mol, without tertiary amino groups. Examples include diamines such as ethylene diamine, hexamethylene diamine, piperazine, 2,5-dimethylpiperazine, 1-amino-3- aminomethyl-3,5,5-trimethyl-cyclohexane (isophoronediamine, IPDA), 4,4'-di aminodicyclohexylmethane, 1,4-diamino-cyclohexane, 1,2-diamino-propane, Hydrazine, hydrazine hydrate or triamines, such as diethylenetriamine. You can be used in proportions of 0 to 2.0 mol / mol component b), in particular especially for chain extension of prepolymers containing isocyanate groups before or especially in the case of triamines after the dispersion in Water. The chain extenders containing amino groups can also be in blocked form, e.g. B. in the form of the corresponding ketimines (see, for example, the CA-PS 11 29 128), Ketazine (see, for example, US Pat. Nos. 42 69 748 and 42 69 748) or amine salts (see US Pat. No. 4,292,226). Even oxazolidines, like they are used, for example, in accordance with US Patents 41 92 937 and 41 92 937 capped diamines are used in the manufacture of the inventions polyurethane dispersions according to the invention for chain extension of the iso cyanate prepolymers can be used. When using the like capped diamines, these are generally combined with the isocyanate Prepolymers mixed in the absence of water and this mixture closing with the dispersion water or part of the dispersion mixed water, so that the corresponding hydrolytically Diamines are released.

The components e) which may be used are Amino alcohols such as ethanolamine, isopropanolamine, methylethanolamine or Aminoethoxyethanol.  

Compounds which have at least one, preferably two groups which are reactive toward isocyanate groups and also ionic groups or by a simple neutral tion or quaternization reaction convertible into ionic groups potentially have ionic group. By introducing the structure Components f) the polyurethanes themselves become dispersible, i.e. H. at the In this case, dispersing agents in water do not become dispersing agents (Protective colloid or emulsifiers) more needed. The introduction of the cationic and anionic groups are made by using (Potential) cationic compounds with opposite Isocyanate groups reactive hydrogen atoms or (potential) Compounds containing anionic groups with isocyanate group reactive hydrogen atoms. To this group from Verbin Examples include tertiary nitrogen atoms Polyethers, preferably with two terminal hydroxyl groups, as they do for example by alkoxylation of two bound to amine nitrogen Amines containing hydrogen atoms, e.g. B. N-methylamine, aniline or N, N'-dimethylhydrazine, are accessible in a conventional manner. The Like polyethers generally have between 500 and 6000 g / mol lying molecular weight. However, the ionic ones are preferred Groups by using comparatively low molecular weight Ver bonds with (potential) ionic groups and with isocyanate groups reactive groups introduced. For example, these are in US-PS 34 79 310 and 40 56 564 and GB-PS 14 55 554 listed. Also dihydroxyphosphonates, such as the sodium salt of 2,3-dihy droxypropan-phosphonic acid ethyl ester or the corresponding sodium salt the non-esterified phosphonic acid, can be used as an ionic structural component can also be used.

Particularly preferred (potential) ionic components f) are N-alkyl dialkanolamines, e.g. B. N-methyldiethanolamine, N-ethylenediethanolamine, Diamino sulfonates such as the Na salt of N- (2-aminoethyl) -2-aminoethane sulfonic acid, dihydroxysulfonates, dihydroxycarboxylic acids, such as dimethylol propionic acid, diaminocarboxylic acids or carboxylates, such as lysine or that Na salt of N- (2-aminoethyl) -2-aminoethane carboxylic acid and diamines with at least one additional tertiary amine nitrogen atom, e.g. B. N-methyl bis- (3-aminopropyl) amine.

The conversion of the first optionally into the polyaddition product built-in potential ionic groups at least partially in ionic Groups are done in a conventional manner by neutralizing the potential anionic and cationic groups or through quarters Nation of tertiary amine nitrogen atoms.  

To neutralize potential anionic groups, e.g. B. carboxyl groups, inorganic and / or organic bases are used such as Sodium hydroxide, potassium hydroxide, potassium carbonate, sodium hydrogen carbonate, Ammonia or primary, secondary and especially tertiary amines, e.g. B. Tri ethylamine or dimethylaminopropanol.

To transfer the potential cationic groups, e.g. B. the tertiary Amine groups in the corresponding cations, e.g. B. ammonium groups are as Neutralizing agents inorganic or organic acids, e.g. B. hydrochloric acid, Acetic acid, fumaric acid, maleic acid, lactic acid, tartaric acid, oxalic acid or Phosphoric acid or as quaternizing agent, e.g. B. methyl chloride, methyl iodide, dimethyl sulfate, benzyl chloride, ethyl chloroacetate or bromine suitable for acetamide. Other suitable neutralization and quaternization means are z. B. in US-PS 34 79 310, column 6 described.

This neutralization or quaternization of the potential ion groups can be before, during, but preferably after the isocyanate polyaddition reaction.

The amounts of the structural component f) in the case of potential ion groups Components taking into account the neutralization or quaternary degree of suitability, is suitably chosen so that the polyurethanes Content from 0.05 to 2 m eq / g polyurethane, preferably from 0.07 to 1.0 and particularly preferably from 0.1 to 0.7 mEq / g polyurethane of ionic Have groups.

The components g) which may be used are preferably monohydric polyether alcohols with a molecular weight of 500 to 10,000 g / mol, preferably from 1000 to 5000 g / mol. Monovalent poly ether alcohols are by alkoxylation of monovalent starter molecules, such as methanol, ethanol or n-butanol available, where as Alkoxylating agent ethylene oxide or mixtures of ethylene oxide with others Alkylene oxides, especially propylene oxide, can be used. In the case of ver However, the use of alkylene oxide mixtures preferably contains them at least 40, particularly preferably at least 65 mol% of ethylene oxide.

Component g) can thus optionally in the polyurethanes present in terminal and / or laterally arranged polyether chains Polyethylene oxide segments can be installed, which in addition to the ionic groups influence the hydrophilic character.  

The connections of the type mentioned within within end and / or pages permanently arranged polyether chains present polyethylene oxide units are used in such quantities, if one makes use of them, that in the polyurethane dispersions from 0 to 10, preferably 0 to 5% by weight, within end and / or laterally arranged polyether chains built-in polyethylene oxide units are present in the polyurethanes. The Total amount of the hydrophilic structural units (ionic groups and However, ethylene oxide units of the last-mentioned type must always be so be chosen that the dispersibility of the polyurethanes in water is guaranteed.

Further examples of in the manufacture of the disper according to the invention Sions usable as components a) to e) are z. B. in High Polymers, Vol. XVI, "Polyurethanes, Chemistry and Technology", by Saunders-Frisch, Interscience Publishers, New York, London, Volume I, 1962, Pages 32 to 42 and Pages 44 to 54 and Volume II, 1964, Pages 5 to 6 and 198 to 199.

As compounds with ethylenically unsaturated groups h) come, for. B. esters of acrylic or methacrylic acid with polyols in question, at least one OH group of the polyol remains unesterified. Hydroxyalkyl (meth) acrylates HO (CH₂) _n OOC (R¹) C = CH₂ (n = 2 to 8; R² = H, CH₃) and their positional isomers, mono (meth) acrylic acid esters of polyether diols HO (CHR²CHR³O) _m OC are particularly suitable (R¹) C = CH₂ (R¹ = H, CH₃; R² = H, CH₃, C₂H₅; m = 2 to 20), trimethylolpropane mono- and di (meth) acrylate, pentaerythritol di- and tri (meth) acrylate or reaction products of epoxy compounds with (Meth) acrylic acid, as z. B. are mentioned in US-A-3 57 221. The adducts of (meth) acrylic acid with compounds of the general formula are particularly suitable for coatings with high hardness

in the Q z. B.

with n = 1-10, -O- (CH₂ ^- ) _m O- with m = 1 to 8 or Q for a radical

stands, this rest z. B. of 4,4'-dihydroxydiphenylmethane, bis phenol A, bisphenol K or nucleus-substituted or hydrogenated derivatives of these connections can derive.

Adducts of (meth) acrylic acid with epoxidized diols can also be used fine such as B. 3,4-epoxycyclohexylmethyl-3 ', 4'-epoxycyclohexane carboxylate.

The adduct of acrylic acid with the bisglycidyl ether is particularly preferred from Bisphenol A.

The polyurethane A) can be prepared by customary methods, such as e.g. B. are described in DE-A-34 37 918 take place.

Preference is given to an inert, water-miscible solution medium, such as acetone, tetrahydrofuran, methyl ethyl ketone or N-methyl pyrrolidone from components a), b), h), optionally c), e), g), h) and f), if f) contains no amino groups, a precursor with end permanent isocyanate groups. The reaction temperature is present preferably at 50 to 100 ° C.

To accelerate the reaction of the diisocyanates, the usual and known catalysts, such as dibutyltin dilaurate, tin II octoate or 1,4-diazabicyclo (2,2,2) octane, may also be used.

To undesired, premature polymerization of the unsaturated groups to avoid, are advantageous already in the manufacture of the poly urethane, polymerization inhibitors added. For this are examples wise quinones, phenothiazine, phenols or phenol derivatives, such as p-benzo quinone, hydroquinone, p-methoxyphenol and the like. a. Suitable connections as they are e.g. B. are described in "Encyclopedia of Polymer Science and Technology", Vol. 7, 1967, p. 644-664 Editors: Mark, Gaylord and Bikales, Interscience Publishers, Wiley + Sons, New York-London-Sydney.  

The polyurethane obtained in this way can optionally be (further) Dilution with solvents of the type mentioned above, preferred low-boiling solvents with boiling points below 100 ° C, at a Temperature between 20 and 80 ° C with amino functional products from Component f) and optionally d) are further implemented.

The transfer of potential salt groups, e.g. B. carboxyl groups or tertiary amino groups, which via component f) in the polyurethane have been introduced into the corresponding ions by Neutra lization with bases or acids or by quaternization of the tertiary Amino groups before or after dispersing the solution in water.

After the solution has been dispersed in water, the organic Distilled off solvent.

The weight fraction of water in the dispersion is generally so dimensioned that aqueous polyurethane dispersions with 10 to 60 wt .-%, are preferably obtained with a solids content of 20 to 50% by weight.

The radiation-curable aqueous binder dispersion according to the invention ent holds in addition to component (A) 5 to 95 wt .-%, based on the Total amount of (A), (B) and (C) of a prepoly dispersed in water mer or prepolymer mixture (B) with a content of 0.1 to 1.0 mol polymerizable ethylenically unsaturated groups per 100 g prepolymer or prepolymer mixture and a molecular weight of 300 to 10,000 g / mol, the K value (measured at 25 ° C. in dimethylformamide is less than 40.

The prepolymer or prepolymer mixture preferably contains 0.1 to 0.5 mol polymerizable ethylenically unsaturated groups.

The molecular weight is preferably 300 to 1000 g / mol. The K value is preferably less than 30, particularly preferably less than 20.

As such, the prepolymer or prepolymer mixture is at 20 ° C and Normal pressure usually fluid.

When using a prepolymer mixture, prepolymers can also be used are set, which are fixed at 20 ° C and normal pressure, as long as the pre polymer mixture is liquid.  

It is not when using liquid and solid prepolymers absolutely necessary, first a liquid prepolymer mixture to manufacture. The individual prepolymers can be separated in water be dispersed. It is only important that the prepolymers in Mix result in a liquid phase and so compared to not flowable polyurethane particles (A) are movable. This will significantly for film formation and formation of a better association contributed.

The prepolymers can be polyesters, polyethers, polyepoxides, Polyurethanes or radically polymerized polymers or copolymers act which by reaction with compounds such as acrylic acid or meth contain acrylic acid polymerizable carbon double bonds.

The following prepolymers are preferred:

• 1. The polyesters are preferably polyesters with an acid number of at most 10 which are composed of (cyclo) aliphatic C ₅ to C ₁₂ or C ₂ to C ₁₂ and / or aromatic C ₅ -C ₁₄ dicarboxylic acids, such as succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, cyclohexanedicarboxylic acid, phthalic acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, itaconic acid or their derivatives, and preferably 2- to 5-valent C ₂ -C ₁₀ -alkylene fetch, such as , propylene glycol, propylene glycols, poly polyethylene glycols, butanediol, hexanediol, neopentyl glycol, hydroxy pivalinsäureneopentylglykolester, trimethylolpropane, glycerin, penta erythritol and α, β-ethylenically unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, cinnamic acid and / or dicarboxylic acid half of monoalcohols such as maleic , Fumaric and itaconic acid semiesters with C ₁ to C ₄ monoalcohols, acrylic acid and M ethacrylic acid are preferred, can be prepared by the usual methods.
• 2. The polyethers are preferably aliphatic polyethers, which by reacting di- or polyhydric, in particular special di- to trihydric C ₂ - to C ₁₀ -alcohols with epoxides, for. B. ethylene oxide or propylene oxide and ethylenically unsaturated alcohols, for. B. allyl alcohol, methallyl alcohol, crotyl alcohol, hydroxyl-containing (meth) acrylic acid esters or preferably ethylenically unsaturated monocarboxylic acids, for. B. acrylic acid or methacrylic acid can be obtained.
• 3. The polyepoxides are preferably polyepoxides with an average of 2 to 4, especially 2 epoxy groups per molecule, for example polyglycidyl ethers of polyhydric alcohols, as they are are mentioned under 1), polyglycidyl ethers of polyhydric phenols, such as Bisphenol A, novolaks, glycidyl esters of polyvalent carboxylic acids, such as they are also mentioned under 1), other glycidyl compounds for example triglycidyl isocyanurate, which with ethylenically un saturated carboxylic acids as they are also mentioned under 1) special acrylic acid and methacrylic acid are implemented.
• 4. The polyurethanes are preferably a polyurethane which may contain urea groups and which is composed of C ₂ -C ₁₀ -alphatic and / or C ₅ -C ₂₀ aromatic polyisocyanates, preferably diisocyanates, for example tetramethylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, Diphenylmethane diisocyanate, tolylene diisocyanate, naphthylene diisocyanate, 4,4'-diphenyl ether diisocyanate, optionally resulting di- or trimers z. B. their isocyanurates, biurets, allophanates, and their reaction products, and hydrogen-active compounds, such as. B. polyhydric alcohols mentioned under 1), polyfunctional amines and / or amino alcohols, and hydroxyl-containing C ₁ - to C ₁₂ -alkyl (meth) acrylates, such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate and / or butanediol mono (meth) acrylate. The sum of the gram equivalents of the hydroxyl and amino groups reactive towards isocyanate, based on 1 gram equivalent of isocyanate, is preferably 0.95 to 1.05.
• 5. The radically polymerized polymers or copolymers are preferably copolymers of styrene, and / or acrylic esters, for. B. C ₁ -C ₁₂ alkyl (meth) acrylates, with small amounts of functionalized monomers, for. B. C ₁ -C ₈ hydroxyalkyl (meth) acrylates or glycidyl (meth) acrylate, (meth) acrylic acid, maleic anhydride, isocyanato ethyl acrylate, which with ethylenically unsaturated compounds such as. B. under 1) or mentioned above, but in particular acrylic acid and methacrylic acid, are implemented, and thus have a content of polymerizable carbon double bonds.

Polyesters, polyethers and polyepoxides are particularly preferred. The Prepolymers can also be amine modified, e.g. B. by the addition of primary or secondary amines on double bonds (Michael addition). Component (B) can first be in an organic solvent or  Solvent mixture, e.g. B. in the manufacture of components (B) used solvents are present in solution. Suitable organic solution means are z. B. tetrahydrofuran, dioxane, acetone, methyl ethyl ketone, pro Panols, butanols, ethyl acetate, butyl acetate, methylene chloride, xylenes or Toluene; methyl ethyl ketone, tetrahydrofuran, isopropanol and Isobutanol. The solution of component (B) is then dispersed in water and distilled off the organic solvents. Component (B) can also be dispersed directly in water.

In general, the solids content of such aqueous dispersions is of components (B) 20 to 80 wt .-%.

Component (B) can be self-dispersible so that no dispersing auxiliary (protective colloid or emulsifier) is required. Is preferred it is not self-dispersible and is made with the help of a protective colloid dispersed. The water is therefore already before the dispersing Components (B) or the organic solution of components (B) Protective colloid added.

The protective colloid is in this case generally in amounts from 0.1 to 30, preferably 3 to 12 wt .-%, based on (B). It deals are preferably water-soluble high-molecular organic Connections with polar groups, such as. B. polyvinyl pyrrolidone, Copolymers of vinyl propionate or acetate and vinyl pyrrolidone, partially saponified copolymers of acrylic ester and acrylonitrile, Polyvinyl alcohols with different residual acetate content, cellulose ether, Gelatin or mixtures of these substances. Particularly preferred Protective colloids are polyvinyl alcohol with a residual acetate content of less than 35, in particular 5 to 30 mol% and / or a vinyl pyrrolidone / vinyl propionate copolymer with a vinyl ester content of less than 35, esp special 5 to 30 wt .-%.

In addition, nonionic, in special cases also ionic emulsions gates can be used. Preferred emulsifiers are longer chain alcohols or phenols of different degrees of eth and / or propoxylation (Adducts of 4-50 mol ethylene oxide and / or propylene oxide). Especially before combinations of the above-mentioned protective colloids with the like emulsifiers, because they give finer dispersions will.

The binder dispersion according to the invention contains as component (C) 0 to 30% by weight, preferably 0.1 to 10% by weight, particularly preferably 0.5 to 10 wt .-%, based on the total amount of (A), (B) and (C) one protective colloids mentioned above.  

For the production of the radiation-curable binders according to the invention dispersions, the aqueous dispersions of components (A) and (B) be mixed.

An aqueous dispersion of a self-dispersible is preferred Polyurethane (A) with the aqueous dispersion of a prepolymer (B), which is dispersed with the help of a protective colloid.

The binder dispersion according to the invention preferably contains 19.9 to 80 wt .-%, particularly preferably 40 to 79.5 wt .-%, based on the total amount of (A), (B), and (C) of components (A).

The proportion by weight of components (B) is accordingly preferred 19.9 to 80 wt .-%, particularly preferably 20 to 59.5 wt .-% based on the Total amount of (A), (B) and (C).

The solids content of the binder dispersion of the invention can ent can be set according to the desired viscosity. In general the solids content is between 20 and 80, in particular between 20 and 70% by weight.

The dispersions according to the invention can contain further additives, e.g. B. pigments, Dyes, fillers and auxiliaries common in coating technology contain.

The dispersions are used for radiation curing by UV light Photoinitiators added.

Suitable photoinitiators are, for. B. benzophenone, alkylbenzo phenones, halogen methylated benzophenones, Michler 's ketone, anthrone and halogenated benzophenones. Benzoin and its derivatives are also suitable. Also effective photoinitiators are anthraquinone and numerous of its derivatives, for example β-methylanthraquinone, tert-butylanthra quinone and anthraquinone carboxylic acid esters and acylphoshin oxides, e.g. B. Lucirin® TPO. The photoinitiators can also be attached to the polymer backbone be bound, e.g. B. by copolymerization of with methacrylate groups functionalized photoinitiators.

The photoinitiators, depending on the intended use of the invention Masses in amounts between 0.1 and 20% by weight, preferably 0.1 to 5% by weight, based on the polymerizable components, can be used as a single substance or, because of the more advantageous synergistic Effects can also be used in combination.  

Advantageous additives that further increase the reactivity can lead to certain tert. Amines such as B. triethylamine and tri ethanolamine. They too can be used in amounts of up to 5% by weight, based on the polymerizable components can be used.

Finally, it should also be mentioned that the dispersions according to the invention can also be thermally cross-linked. Here is the addition of Initia gates that form radicals at elevated temperatures are necessary. Usable are z. B. dibenzoyl peroxide, cumene hydroperoxide or azodiisobutyric acid dinitrile. Further examples of suitable initiators are in "Polymer Handbook ", 2nd edition, Wiley & Sons, New York.

The dispersions of the invention can be used for the production of Coatings are used.

You can e.g. B. by spraying, pouring, printing or knife coating on substrates such as metal, plastic, glass, wood, paper, cardboard, leather or textile to be brought.

In radiation curing, the coatings are generally up to 30 minutes Preheated at temperatures up to 100 ° C and then briefly one Exposed to UV or high energy electron beams. For this, the UV or electr. usually used for the hardening of coatings Tron radiation sources used. To keep the preheating times as short as possible to keep are relatively low molecular weight for viscosity reasons polymers preferred.

For porous substrates, such as leather, paper, wood, are only very short preheating times required, since the bulk of the water from Underground is recorded; sometimes preheating can to be waived.

The coatings also have very good elastic properties create a great hardness.

The adhesion of the coatings and chemical resistance is also very high Good.  

example 1 Polyurethane dispersion a ₁ )

200 parts by weight of a polyester made from adipic acid, isophthalic acid (Molar ratio 1: 1) and 1.6 hexanediol (OH = number 112), 43 parts by weight 1,4-butanediol, 60 parts by weight of bisphenol A diglycidyl ether acrylate (adduct of 2 mol of acrylic acid on bisphenol A diglycidether, 53 parts Dimethylolpropionic acid and 100 parts of N-methylpyrrolidone were added Dewatered at 70 ° C. in vacuo and with 322 parts by weight of isophorone diisocyanate implemented at 90 ° C up to an NCO content of 2.75 wt .-%. To Diluted with 800 parts by weight of acetone gave 32 parts by weight Dimethylethanolamine added and the solution in 1500 parts by weight Water dispersed within 10 minutes. After 5 minutes, 21 parts were added Isophoronediamine and 9 parts by weight of diethylene triamine in 140 parts by weight Water added. Acetone was distilled off. Part of the dispersion was dried at room temperature, whereby a film was formed which in Dimethylformamide was insoluble.

Prepolymer dispersion b)

18 wt% bisphenol A diglycidyl ether acrylate
27% by weight of an alkoxylated trimethylolpropane acrylate (MW: 500 g / mol; 100 Pa · s at 23 ° C, Laromer® LR8748 BASF AG)
5 wt .-% polymer of N-vinylpyrrolidone and vinyl propionate in a weight ratio of 66:34.
50% by weight water

117 g of the polyurethane dispersion were mixed with 30 g of the prepolymer dispersions mixed, 2 g of a photoinitiator benzophenone / 1-hydroxycyclohexyl phenyl ketone (Irgacure® 500, from Ciba-Geigy AG, added and the solid Content of the dispersion adjusted to 30 wt .-% with water. The Weight ratio polyurethane / prepolymer was 70:30.

The dispersion was made on semi-matt art paper (KD paper) applied, dried at 40 ° C for 20 min and under one High pressure mercury lamp (120 watt / cm) at a distance of 10 cm on one Band passed. An 8 µm layer could run at a belt speed greater than 78 m / min can be hardened scratch-resistant compared to a fingernail.  

A 40 µm layer on glass had after 2 times exposure with a tape speed of 10 m / min an oscillation damping value (DIN 53 157) of 115 s. The Erichsen indentation (DIN 53 156) of a 20 µm thick at a 2 times hardened layer on bonder with a belt speed of 10 m / min sheet 132 was 9.8 mm. The adhesion of this layer with and without a grid cut, chemical resistance (DIN 68 860 B), smoothness and Grindability was very good.

Example 2 Polyurethane dispersion a ₂ )

200 parts by weight of a polyester made from adipic acid, isophthalic acid (Molar ratio 1: 1) and 1,6-hexanediol (OHZ 112), 80 parts by weight 1,4-butanediol, 60 parts by weight of bisphenol A diglycidyl ether acrylate, 54 parts by weight of dimethylolpropionic acid, 0.1 part by weight of p-methoxyphenol and 100 parts by weight of N-methylpyrrolidone were dewatered at 70 ° C. in vacuo and with 411 parts by weight of isophorone diisocyanate at 90 ° C up to one NCO content of 2.34 wt .-% implemented. After dilution with 800 parts by weight Acetone was added 28 parts by weight of dimethylethanolamine and the solution dispersed in 1000 parts by weight of water within 10 min. After 5 min 21 parts by weight of isophoronediamine and 9 parts by weight of diethylene triamine were added 40 parts by weight of water were added. Acetone was distilled off. The Polyurethane was insoluble in dimethylformamide.

Analogously to Example 1, a ₂ and b) were prepared from a dispersion with a solids content of 30% by weight, the weight ratio of the polyurethane to the prepolymer being 70:30.

The fingernail scratch resistance was achieved at 45 m / min. The pendulum damping was 105 s, the Erichsen depth over 10 mm. Liability, chemicals Line resistance and smoothness were very good.

Comparative example

The solids content of the prepolymer dispersion b) was 30% by weight posed. The fingernail scratch resistance was achieved at 10 m / min. The pendulum damping value was 130 s and the Erichsen depression was only 3 mm. The Chemical resistance was very good, however liability was only satisfying.

Claims (4)

1. Containing radiation-curable, aqueous binder dispersions

• A) 5 to 95% by weight, based on the total amount of components (A), (B) and (C), of a polyurethane dispersed in water which has a K value greater than 40 (measured in dimethylformamide) or in dimethylformamide is not soluble and has a polymerizable ethylenically unsaturated group content of at most 0.2 mol per 100 g of polyurethane, and
• B) 5 to 95% by weight, based on the total amount of components (A), (B) and (C), of a prepolymer or prepolymer mixture dispersed in water with a content of 0.1 to 1.0 mol of polymerizable ethylenically unsaturated Groups per 100 g of prepolymer or prepolymer mixture and a molecular weight of 300 to 10,000, the K value (measured in dimethylformamide) being less than 40, and
• C) 0 to 30% by weight, based on the total amount of components (A), (B) and (C), of a protective colloid.

2. Process for the preparation of binder dispersions according to An claim 1, characterized in that an aqueous dispersion of a self-dispersible polyurethane (A) with the aqueous dispersion of a prepolymer (B), which with the help of a protective colloid is dispersed, is mixed. 3. Use of aqueous binder dispersions according to claim 1 for Manufacture of coatings by exposure to energy rich radiation can be cured. 4. Coated substrates available using a binder dispersion according to claim 1.